The Gunners took advantage of Manchester United's defeat by Manchester City to move five points clear after beating Blackburn.

The reversal of fortune gives an added edge to the FA Cup fifth-round encounter tomorrow at Old Trafford between the arch-rivals.

United boss Ferguson said: "I am not happy we are five points behind them.

"You want to be leading at this stage of the campaign.

"However, I have to say Arsenal are looking more compact and more solid than they were last season."

Ferguson is perplexed at marking his 100th FA Cup game by facing a Premier League side in the competition for the third time in succession this season.

First of all Aston Villa were dispatched, then Carling Cup finalists Tottenham, both at Old Trafford.

Ferguson quipped: "If we get through this one, I am going to the draw!"

He insists he has no alternative but to shuffle his pack with a Champions League game to follow against Lyon on Wednesday.

He said: "You cannot (keep the same side) in every game. That is why clubs have squads of 22 players.

"You cannot go back to the days when Liverpool won the league with only 14 players to call on."

There is plenty of history between United and Arsenal but Ferguson has seen a change in the landscape.

He said: "We both have different teams today and as a result it is now less fractious."

Ferguson has called for a revival of the spirit of 1958 following the derby defeat as his team prepare for the fifth-round tie.

He claims his side were affected by the sense of occasion at Old Trafford, where the 50th anniversary of the Munich air crash was superbly commemorated.

Ferguson said: "I have a feeling the emotions got to our players.

"The minute's silence was very emotional - it got to me.

"Certainly it was one of the worst performances you would have expected from a Manchester United side. But we have to put that behind us.

"Back in '58 it was a test for the club - now we have a test."

Ferguson has additional attacking options to call on as Wayne Rooney is free from suspension while Louis Saha has recovered from a knee injury.

Saha could start after a six-match absence while Rooney is eager to return to action.

Ferguson said: "Of course you always miss a player of Wayne's quality.

"However we have a strong squad again and I am glad Louis is back.

"He has had a frustrating two or three years but he is a fantastic player.

"It is great to have him again at this time of the season as he adds something different to the team."

Meanwhile Ferguson is convinced Gary Neville will overcome his injury concerns, which centre around a long-standing ankle problem.

"What Gary needs is a bit of luck," said the United boss.

"He's had setback after setback.

"It is only because of his character he is able to persist in his efforts to get back.

"He is getting all the help and encouragement we can give him.

"Gary is not far away but what he cannot afford is another niggling injury, which can happen."